


M O O N C H I L D

by ningdungie



Category: TOMORROW X TOGETHER | TXT (Korea Band)
Genre: Aged-Up Character(s), Alternate Universe - Vampire, Blood Drinking, Eventual Romance, Human Huening Kai, M/M, Mating Bites / Bonds, Protective Choi Soobin, Supernatural Elements, Vampire Bites, Vampire Choi Soobin, Vampire Knight Inspired
Language: English
Status: In-Progress
Published: 2020-06-15
Updated: 2020-06-18
Packaged: 2021-03-03 23:20:56
Rating: Mature
Warnings: Graphic Depictions Of Violence
Chapters: 2
Words: 4,110
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/24743749
Author URL: https://archiveofourown.org/users/ningdungie/pseuds/ningdungie
Summary: Vampires are creatures of the night, beasts in disguise and shaped like a man, who feed on human blood. Those who know the existence of these creatures are sworn to secrecy, and are awarded gratefully: immortality, wealth, whatever the holder of the secrets desires.Huening Kai is one of these lucky people. Except, he might be notthatlucky.
Relationships: Choi Beomgyu/Choi Yeonjun, Choi Doyoon/Kang Taehyun, Choi Soobin/Huening Kai, Choi Yeonjun/Huening Kai
Comments: 8
Kudos: 59





	1. PROLOUGE

**Notes for the Chapter:**

> hiii this is my very first au in ao3!! warning for blood, murder, violence ahead, hope you guys like it :))

The ground was frozen solid and cold as the young boy's bare feet touched it, sending shivers all over his body. The wind was strong, getting stronger by the minute, and it blew in all directions, causing snow to blow into his glassy eyes, making him flinch at the touch. The coldness caused his small body to convulse. He tried to wrap his coat around his small frame, but the thin material did nothing of blocking the harsh weather.

He looked around, seeing nothing but trees surrounding him and snow beneath him. He knew he was in a forest because of the scenery, but he had no recollection of how he had gotten there and why he was there in the first place.

 _What is the place?,_ his eight-year-old mind thought, and more importantly, _Who am I?_

A soft moan filled the air. The boy looked around frantically, trying to find where the sound originated. He caught sight of a black figure approaching him, but because of the lack of light from the stars because of the clouds and snow that was blowing in the wind blocked him from seeing who was coming near him.

"W-Who's there?" he asked, his voice sounding weak in the howling wind.

He heard a chuckle as the black form stepped closer, just enough to reveal its identity. The boy couldn't help but gasp at the look of the man before him. He was an older man, probably in his thirties counting the start of small wrinkles beginning to form on his face; the man stood a good six feet tall and hard a large trench coat covering his body, hiding what he wore underneath. The man was pale, as white as the snow, and his shoulder length blond hair blew in the wind as it blew. What caused the boy to gasp was that the man's eyes were red, blood red, and blood seemed to be dripping from his mouth, which was turned up into a smirk, which revealed a set of two teeth that seemed to be longer than the rest.

The boy knew what this man was that was standing right in front of him, not five feet away: Vampire.

"Oh my, you poor dear boy. How long have you been out here? It's below freezing and you barely have anything on..." the vampire said as he stepped a foot closer to the boy. "Where are your parents. Surely they must be worried about you..."

"I-I don't know..." the boy said as he gave him a confused look.

The vampire grinned wider, showing his teeth perfectly. "Ah I see. You have no idea who you are then?" The boy shook his head. "Well, that's good for me then. But as for you, I am afraid it would bring you to an end..." the vampire said as he grabbed the boy by the throat, lifting him easily off his feet. The boy choked as he grasped the man's solid arm, clawing at it, trying to get him to release him...with no effort at all.

"P-Please! L-let me go!" the boy choked out. "I don't wanna die!"

The vampire licked his lips. "Well, I didn't either, and now look at me. I'll be sure to make it quick," he promised as he leaned towards the boy, fangs outstretched.

Not wanting to look, the boy squeezed his eyes shut and screamed, hoping someone would hear him. Hoping someone would hear him...and save him.

The next thing the boy knew, he was dropping to the ground. He quickly opened his eyes to see a figure looming over the vampire as he lay on the snowy ground, the snow looking the color of his blood as he bled out.

"Please don't hurt me!" the vampire said as he looked up at the looming figure. "I'm just trying to feed myself, survive. You know what it's like. And he smelt so good, I just-" he cut off as the figure swiftly kicked him in the face, causing him to spit blood.

"Don't try explaining yourself, I saw what you were doing; attacking a poor innocent little boy. All you rogues make me sick," the figure said in a alluring voice, one that caught the boy's attention. The boy watched as the figure grabbed the vampire's head a twisted roughly; with a sickening snap, the boy watched as the figure ripped the head off the vampire, throwing it into the forest a few feet away.

Then the figure turned and stared at the boy, causing the boy to gasp-the figure turned out to be the most beautiful boy he had ever seen. The boy's skin was a light olive color but was a little pale as well like the vampire's. At the moment his eyes were a gleaming red as well as he licked blood from his fingers and approached the boy. He had a medium-built body and couldn't be but just a couple of years older than the boy and stood just about a foot taller. He had surprisingly purple-colored hair that had just enough gel in it to keep it tame but natural at the same time. As he leaned down towards the boy, the younger noticed that his eyes had changed, and were now a hazel color.

"Are you okay, Kai?" he asked in a gentle and loving voice.

The boy looked straight into his eyes. "K-Kai?"

The figure seemed to frown a little. "Yes, that is your name. Do you not remember?" The boy shook his head. "That's okay, I'm here to help you, take you home."

The boy called Kai blinks. "H-Home?"

The man nodded. "Uh-huh. Your father is worried about you. Let's get you home okay?" he said, holding out his hand, which the little boy took.

"W-What's your name?" the boy asked as the other picked him up easily, placing a light kiss on his forehead as he did so.

The figure smiled as he said, "Soobin, my name is Soobin."

**Notes for the Chapter:**

> tell me your thoughts please!


	2. Chapter 2

**Notes for the Chapter:**

> sorry it took so long!! enjoy reading :))

Nineteen-years-old Huening Kai couldn't help but roll his eyes as he watched the Day Class students surrounded the entrance of the Night Class dormitories, all was gazed and eager looks on their faces. As usual, they wanted to see the Night students as they exited. That's why it was his duty to maintain peace and to make sure they kept their distance.

"Alright everyone! Stop blocking the entrance!" he yelled as he ushered them away so each student was standing a sufficient amount away from the entrance, making sure the Night students had enough room when they did exit their building. "Dare I ask why each and every one of you want to crowd around like a freaking fan club every day? The Night students are just like us, so what makes them so special?" he said with feigned ignorance.

Deep down inside, though, he knew that he was lying his ass off. He knew what truly hid under the Night class's uniform.

He ran his hand through his chestnut hair, which was usually coiffed to perfection, though he knew now was not the case. He didn't really care what it looked like right now since it was after school because that was when his Prefect duties really kicked in, and that was stressing enough.

"Kai, you know they won't stop, so there is no point in yelling at them," Kang Taehyun, his friend for two years said as he came up beside him. "You know they are smitten by the Night Class, just like I was before I got Doyoon."

Kai couldn't help but roll his eyes again. Choi Doyoon was one of the Night Class students, and the two had been dating for over a year now. He sighed. "Yes, I know that Taehyun. But it doesn't mean that it still does not annoy me to no end!"

Taehyun chuckled. "I know, but when you look at them you kinda can't help yourself. Each and every one of them is breathtaking..." he stated as his eyes drifted to the entrance, where the double doors opened, revealing the Night Class students on the other side. Once they started walking towards the entrance, the "fan club hysteria" began.

Here we go, Kai said as one by one the Night Class students filed out of the dormitories. Kai could see the appeal that everyone could see. Each and every single one of the Night Class students were the best looking people he had ever seen. He watched as Park Jimin and Jung Hoseok strolled out, hand-in-hand, and waved at a couple of girls, who seemed to faint at the sight. Following them was Kim Seokjin, his short black hair styled to perfection, who seemed to make his way to one of the new students in the Day Class, and give him a chaste kiss before winking and walking away, making the poor boy fan himself. I wonder if he knows, Kai thought to himself as he watched Kim Taehyung walk out with his upperclassmen Jeon Jungkook in front of him, their arms wrapped around each other. He gave Jungkook a glare, and he mouthed "sorry" as Taehyung snickered. He was going to have to get onto those two later; they knew they had to have permission before Jungkook was allowed in the dormitories!

Sighing, he watched as the last of the Night Class students filed out, when he yelled, "Alright, that's everyone! Now leave and get to your own dormitories now! The Night Class has an image to uphold and they cannot do that with all of you acting like their fan club!" A few people gave him choice looks but turned to leave before they noticed someone walking up behind Kai, so they stayed rooted to the spot and just began another progression of squealing.

"Oh, for the love of Jesus! What are you guys doing now?" he asked as he turned around...and froze on the spot.

Behind him not only stood the most amazing person ever but also the savior of his life: Choi Soobin. Now that they both had grown, Soobin had become like a Greek God in Kai's dreams. He kept his hair the same, his hazel eyes always seemed to blaze when he was around Kai, his sharp eyebrows perfect on him even if Kai thought on anyone else would look horrible. And the blue uniform with red piping hugged his body just perfectly. Kai could feel himself getting lightheaded as he smiled.

"Hello, Hueningie," he said in his soothing voice.

"H-Hi Soobin-hyung! Sleep well?" he asked as the male walked up so he was only a few inches away from Kai.

Soobin gave Kai a dazzling smile as he said, "Yes, I did. And it was all thanks to you, cutie."

Kai simply shrugged. "It was nothing, just doing my job as a Prefect."

Soobin chuckled as he took his thumb and swiped it along Kai's smooth and pale cheek. "You do a wonderful job, as always. I on behalf of the Night Class would like to thank you for it. You work hard, and I don't think we express our gratitude enough. Plus we know how difficult our secret is that you have to keep."

"Thank you, and I would rather die then tell the secret," Kai said with a blush. One thing no other knows except a few of the chosen like Kai and Taehyun know about the Night Class that anyone else knows: the Night Class is full of nothing but Vampires.

Actually, it's filled with Purebloods and Vampires. Purebloods are those who are born vampires, and they are the only ones able to change others into vampires as well, which is why they rule the vampire world. Vampires are created for a multiple of reasons: friendship, gratitude, and for the select few-to be a Pureblood's mate, the one and only that can be with a Pureblood.

"I'm glad to hear that," Soobin said, grabbing Kai's hand a pressing a kiss to his knuckle. "But I'd like it if you wouldn't die, because you are a keeper."

Kai was about to reply, before he felt his hand yanked from Soobin's grasp and a tightening go around his wrist. He looked up to see his step-brother, Choi Yeonjun, glaring down at Soobin.

"I think it's time you get to class. Wouldn't want you to be late," he said with a cocky attitude, which Kai silently laughed at because really Yeonjun wasn't like this, he was really just a big moron most of the time. For now, though, he was annoyed because, as much as he loved it when Yeonjun became the "defensive big brother", he was embarrassed because he was doing it towards Soobin.

"Yeonjun-hyung!" Kai said as he smacked the boy's arm. "Not cool at the moment!"

Soobin chuckled at the two. "You do speak the truth. I must go now, but I will see you both later. Oh, and Yeonjun, call or text Beomgyu when you get the chance. He said something about you two going on a date this weekend?" Soobin said before winking at Kai and walking away, making the remaining students swoon at his beauty.

"You have a date with Beomgyu this weekend?" Kai asked as he and Yeonjun guided the Day Class students to the dormitories.

Yeonjun nodded. "Yeah. I finally got the guts to ask him out, after you gave me that pep talk. I'm taking him out on Saturday since it's 'Valentine's Day' and everything. Thought it would be romantic," he said before whispering, "It's not everyday a you get to date a vampire, and a Pureblood at that."

Kai nodded, because he did agree with Yeonjun on that. Purebloods were known not to show interest in humans at all unless the human was "the one", their mate. Kai had noticed a couple of weeks ago when he and Yeonjun had walked past Beomgyu; he had looked up at Yeonjun and seemed to sniff the air, his eyes rolling as he quickly turned around before anyone had noticed and sprinted off. Kai had mentioned it to Yeonjun, Namjoon, and Yeonjun's Mom, that night and they had come to the decision that Yeonjun had to be Beomgyu's mate; so after a strict talk from Kai, Yeonjun had agreed to ask Beomgyu out.

Kai smiled at his brother. "I'm glad you're finally going out. I've been hoping that you would find someone Yeonjun, and Beomgyu seems to be perfect for you."

Yeonjun gave Kai a goofy smile. "Thanks. And I hope the same with you, man. One day you'll find the right guy. He's out there somewhere."

Kai sighed. "No, he's here. He just seems not to notice me..."

Yeonjun laughed. "If you're talking about Choi Soobin, then that would make you wrong. He notices only you."

Kai bumped his shoulder against Yeonjun's. "Not romantically. I'm just that scared little boy he saved ten years ago and brought me home to my father, who is his automotive instructor here. I mean nothing more to him." Though sometimes I wish I did, he added silently.

"Whatever dude. I ain't going to argue with you," Yeonjun said, dropping the subject. "Can I ask you a favor?"

"Shoot."

"Will you help you plan Beomgyu and I's date? I want it to be perfect..."

Kai shrugged as he grabbed the underside of his arm, walking towards their little apartment where their parents were waiting. "Sure, why not. You know how much I love planning events anyhow!"

Kai grimaced at the sound of his voice as a sharp pain coursed through his head. Damn, the headache was back again. He would have to do something about that later. For now, he had plans to draw up.

* * *

"The Blood-Tablets are a success. Vampires worrying about starving from an insufficient amount of blood will be a thing in the past," Principal Bang Sihyuk said as he smiled at Namjoon and Soobin, who sat across from him. "And you and the Night Class are positive that they are working, Soobin-ssi?"

Soobin nodded. "Most definitely, sir. In fact, I just had one earlier this morning. My appetite has been sated...well, aside from earlier. But that was easily taken care of."

Namjoon noticed that Soobin fidgeted in his seat. He asked, "Was it because of Kai?"

Namjoon didn't bat an eye as Soobin nodded. "It was sir," Soobin replied, remembering the way Kai's smell wrapped around him earlier when they were standing outside. "Honestly Namjoon, it is taking more and more resistance Namjoon on my part. He has grown into such a beautiful creature, and I am afraid of losing control when I am around him. The time is near..."

Namjoon sighed as he took of his baseball cap, rubbing his bald head. "I know. His twentieth birthday is next month, and I remember the pact."

Soobin growled. "Oh really? Surely if you truly remembered the pact then you would have given Kai to me months ago and he would have been mine already! You both know exactly what he is. You know the longer he stays that way, the more danger we are putting him in! He belongs to me, damn it, and I want everyone to know that!"

Namjoon grimaced, looking up at the boy whom he had considered another son many years ago. Right now that said boy looked at him with red tinged into his hazel eyes, showing off his annoyance.

"Soobin, calm down. I know," Namjoon said comfortingly. "Kai has belonged to you ever since Jungah conceived him. I knew that when I married her and we decided to have him. I know what Kai is, but he is still my son! I know it's hard, Soobin, but you know Kai has to make the decision in the end. Not me, not you, not anyone else...him. You cannot force him to do anything, that was also part of the pact. You have to earn his trust." Namjoon took a deep breath and tried to calm himself. He didn't need to have another heart attack, not now. "Kai is in love with you, Soobin; he has been since that snowy night, so I know when the time comes he will accept your proposal. You have to ease him slowly into the transition, because if you do not you will end up killing him. I love you Soobin, I think of you as my son just like Yeonjun, but you will not kill my flesh and blood by not abiding by the pact."

Soobin let Namjoon's words sink in, sighing as he sunk into the plush leather chair, wishing it would swallow him up sometimes. "I know Namjoon. I love Kai, and he will come to love me the way I love him. I apologize for my outburst. I'm just getting...testy. The more time I spend with Kai, the harder it is for me to resist him. And if I bite him, you know what will happen..."

Namjoon nodded. "I do. But I also know before you do you will stop yourself, because no matter what you do not want to lose Kai. I am confident you will make him comfortable enough to become a vampire...though in reality he kinda already is."

"Hush Namjoon. My door might be shut but I do not want any stragglers hearing," Sihyuk added quickly.

"I apologize," Namjoon said, dropping his voice. "Soobin, when will you start courting Kai? I hope it is soon..."

Soobin gave a wicked smile, flashing his pointed teeth. "Why Kai's favorite holiday of course. Even if he says he is not a fan of Valentine's Day, I know for a fact that that is a lie..."

* * *

Kai sighed, watching as the couples walked around the school grounds, basking in the Valentine's Day glow. He wished he could be like them. He wanted his Prince Charming to come and sweep him off his feet and make him feel special today. Everyone was lucky to have someone special, and he wished he could experience that. Even Yeonjun seemed to be on cloud nine today before he left. From what Kai knew, he and Beomgyu had talked over the phone and after classes for hours and had gotten to know each other a little better.

Kai tried to shake the thoughts out of his head as he stood up and stretched his limbs. Tonight he had to keep a close eye on the students since he was alone on patrol for the Day and Night Class students. His duty was to make sure the Day Class was safe from the Night Class, because at any sign of possible blood could drive the students crazy.

He decided to take a walk in the woods that surrounded the school, knowing for a fact that a couple of couples liked to make out in them. He didn't need anything getting out of hand, especially since it was getting late, almost midnight.

As he was walking, a root seemed snag at his pants, because next thing he knew he was falling the ground. He brought his palms out, trying to break his fall. When they hit the ground, he felt pain go across the bottom of them, and he whimpered. He sat up, looking at them in the moonlight: they were bleeding, dirt encrusted into the wounds.

"Son of a..." he said as he picked himself off the ground, wincing as he felt a pain in his knee as well. "Today is just not my day..."

He heard a rustling behind him and heard, "You can say that again."

Kai turned to see Hwang Hyunjin, one of the Night Class vampires, standing behind him, giving him a toothy smile. "Fall down on your fairy ass Huening? That's just sad..."

Kai rolled his eyes. "Fuck you, Hwang. Wasn't my fault, stupid ground made me trip," he replied as he tried wiping some of the blood on his black coat. "What are you doing out here, anyways? Shouldn't you be in the dormitories or out on a date?"

Hyunjin shook his head. "Nah, thought I'd come out here and see if I could find something to eat, since those nasty ass Tablets ain't doing shit for me."

"Whatever, you probably haven't even tried them," Kai said before catching on to what Hyunjin said. "Wait, you aren't out here looking for a human to feed off of, are you? Because if you are, then I'm going to have to report you."

"You ain't going to do shit!" Hyunjin yelled before grabbing Kai by the arm and bringing the boy against his body. "Wanna know why? Because I'm going to kill you, since I've been wanting to do it for such a long time, and nobody will care."

Kai tried to protest, but Hyunjin placed a hand over Kai's mouth, muffling his voice. "I'm going to drain you, and you are going to enjoy it because of the fag you are, then I'm going to rip your body to sheds, so no one can find you."

"Don’t touch him with that filthy hands of yours!" someone roared behind them. Kai knew that voice anywhere, and he thanked whoever was listening as he saw Soobin come into his line of vision as he watched the pureblood push Hyunjin away into a nearby tree before covering Kai up with his body. "Huenignie, are you okay?" Kai nodded, tears streaming down his face. Soobin kissed his forehead before turning to Hyunjin. "Hwang, you are in so much trouble. Wait until Sihyuk hears about this. You will be expelled and killed!"

Hyunjin spat on the ground before saying, "You have to catch me first!", before he ran into the woods, silently and with inhuman speed.

Soobin growled. He would have followed Hyunjin and killed him himself if it hadn't been for Kai, who had wrapped his arms around himself and started shaking.

"Hueningie, Ningning, I'm going to pick you up and take you to the infirmary, alright?"

Kai looked into Soobin's eyes, which seemed to be asking permission. He could see a flame in those eyes, something he couldn't quite place what it was. Slowly, Kai nodded his head, giving his permission for Soobin to pick him up.

Soobin smiled before wrapping one arm around Kai's back and the other around his legs before picking Kai up, bridal style. At any other time, Kai would have protested being in this position, but for now he could care less.

Soobin whispered a faint "close your eyes", which Kai obliged to, before he began running at an inhuman speed, leaving the forest far behind them.

**Notes for the Chapter:**

> do you like this chapter?? tell me your thoughts please!


End file.
